Surgical fastener applying apparatus with controlled beam deflection

ABSTRACT

A surgical fastener applying apparatus including an anvil half-section having a distal end and a longitudinal axis; a cartridge receiving half-section having a distal end and operatively couplable with the anvil half-section such that the distal ends of the half-sections are in juxtaposed relation; and a deflection control system operatively engaged with and reinforcing the distal end of the anvil half-section when a force is applied to the distal end of the anvil half-section in a direction transverse to the longitudinal axis.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.13/625,153, filed Sep. 24, 2012 (now U.S. Pat. No. 8,701,961), which isa Continuation of U.S. patent application Ser. No. 13/195,898, filedAug. 2, 2011 (now U.S. Pat. No. 8,292,149), which is a Continuation ofU.S. patent application Ser. No. 12/726,608, filed Mar. 18, 2010 (nowU.S. Pat. No. 8,011,552), which is a Continuation of U.S. patentapplication Ser. No. 12/358,332, filed Jan. 23, 2009 (now U.S. Pat. No.7,699,205), which is a Continuation of U.S. patent application Ser. No.11/933,624, filed Nov. 1, 2007 (now U.S. Pat. No. 7,543,729), which is aContinuation of U.S. patent application Ser. No. 10/958,074, filed Oct.4, 2004 (now U.S. Pat. No. 7,296,722), which claims benefit of U.S.Provisional Patent Application Ser. No. 60/512,497 filed Oct. 17, 2003,and the disclosures of each of the above-identified applications arehereby incorporated by reference in their entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to surgical fastener applying apparatusand, more particularly, to surgical fastener applying apparatus thatinclude a deflection control system for controlling and/or reducing therate of deflection of an anvil beam.

2. Background of Related Art

Surgical fastener applying apparatus, for example, surgical staplingapparatus, have been developed in which a staple cartridge receivinghalf-section including a staple cartridge assembly provided at a distalend thereof, is operatively connected (e.g., pivotably connected) to ananvil half-section including an anvil provided at a distal end thereof.The staple cartridge assembly preferably includes a plurality ofsurgical staples which are ejectable therefrom. The staple cartridgeassembly may be manufactured as an integral part of the staple cartridgereceiving half-section, or the staple cartridge assembly may be designedand manufactured as a disposable loading unit for use in a reusablesurgical stapling apparatus.

Typically, when the distal end of the staple cartridge receivinghalf-section is approximated toward the distal end of the anvilhalf-section, to clamp tissue inserted therebetween in preparation forstapling, the opposing surfaces of the distal end of the staplecartridge assembly and the distal end of the anvil assembly are spacedapart by a predetermined distance which is pre-established and fixed foreach surgical stapling apparatus. This spacing is sometimes referred toas the “tissue gap” of the surgical stapling apparatus.

Since it is desirable that the “tissue gap” be substantially uniformand/or “fixed” (i.e., having the same dimension throughout the staplingoperation), in order to form lines of uniform staples along thecartridge, the operator of the surgical stapling apparatus needs toascertain whether the “tissue gap” is loaded with more or thicker tissuethan recommended (i.e., overloaded) which may result in undesired orincreased deflection of the distal end of the anvil half-section and/orthe staple cartridge receiving half-section. As used herein, the term“deflection” is understood to include flexing, bending, deforming,biasing, skewing and the like.

It is desirable that tissue having a thickness larger, preferablyslightly larger, than the height of the “tissue gap” be clamped betweenthe tissue contacting surface of the staple cartridge assembly and theanvil so that when the surgical stapling apparatus is clamped onto thetissue, the tissue substantially fills the entire height of the “tissuegap”. However, it has been noticed that clamping of such tissue betweenthe tissue contacting surfaces of the distal ends of the anvil andstaple cartridge receiving half-sections tends to cause the distal endsof the anvil and/or staple cartridge receiving half-sections to deflect.The greater the initial and/or resultant thickness of tissue clampedbetween the distal ends of the staple cartridge receiving and anvilhalf-section, especially adjacent and at their distal tips, the greaterthe degree of deflection of the distal end of the anvil half-sectionand/or the staple cartridge receiving half-section.

In the past, the deflection at the distal end of the anvil half-sectionwas reduced and/or eliminated by using a relatively heavier construction(i.e., thicker structural elements), a relatively larger construction orrelatively stronger materials. These approaches increase the size and/orcost of the surgical stapling apparatus.

It would be desirable to provide a surgical stapling apparatus thatincludes a deflection control system for controlling and/or reducing therate and/or degree of deflection of the distal end of the anvilhalf-section when tissue is clamped between the distal ends of the anviland staple cartridge receiving half-sections.

It would also be desirable to provide a surgical stapling apparatus thathas a deflection control system which allows rapid initial deflection ofthe distal end of the anvil half-section to a specific value and whichthereafter causes a decrease or reduction in the rate and/or degree ofdeflection in a predetermined manner.

It would also be desirable to provide a surgical stapling apparatus thatincludes a deflection control system which allows rapid initialdeflection of the distal end of the anvil half-section to efficaciouslyachieve the optimal tissue gap when clamping relatively thin tissue andwhich thereafter reduces the rate of deflection in relatively thickertissue to maintain the tissue gap as close as possible to the optimaltissue gap.

Surgical stapling apparatus constructed in this manner would allow forrapid deflection of the distal end of the anvil half-section to aspecific value followed by a decrease in the rate of deflection of thesame. Accordingly, the distal end of the anvil half-section is able todeflect quickly to the optimal tissue gap in relatively thin tissue anddeflect slowly in relatively thicker tissue to remain as close aspossible to the optimal tissue gap.

SUMMARY

According to an aspect of the present disclosure, a surgical fastenerapplying apparatus is provided including an anvil half-section includinga distal end and a proximal end defining a longitudinal axis, acartridge receiving half-section including a distal end, and adeflection control system operatively associated with the anvilhalf-section. The cartridge receiving half-section is desirablyoperatively couplable with the anvil half-section such that the distalend of the anvil half-section is movable into juxtaposed relation to thedistal end of the cartridge receiving half-section. A tissue gap isdefined between the distal end of the anvil half-section and the distalend of the cartridge receiving half-section when the anvil and cartridgehalf-sections are coupled together.

The deflection control system is configured and adapted to reinforce thedistal end of the anvil half-section when a force is applied there in adirection transverse to the longitudinal axis.

In addition, the anvil half-section defines a tissue contacting surface.Accordingly, the deflection control system reinforces the distal end ofthe anvil half-section when a force is applied to the distal end of theanvil half-section in a direction transverse to the longitudinal axisand normal to a plane defined by the tissue contacting surface of theanvil half-section.

In one embodiment, the anvil half-section includes a U-shaped channelmember having a pair of side walls interconnected by a base wall. Inthis embodiment, the deflection control system is operatively associatedwith the channel member. The deflection control system is desirablyoperatively disposed within the channel member.

According to one embodiment, the deflection control system can include aU-shaped channel section having a pair of side walls interconnected by abase wall. Preferably, the base wall of the channel section of thedeflection control system is adjacent, more preferably in contact withthe base wall of the channel member of the anvil half-section, and theside walls of the channel section are disposed interior of and adjacentthe side walls of the channel member. It is envisioned that each sidewall of the pair of side walls of the channel section has a height whichis less than a height of a respective one of the pair of side walls ofthe channel member thereby defining a reveal along each side wall of thepair of side walls of the channel member. Preferably, the relativeheight of each side wall of the pair of side walls of the channelsection is uniform along a length thereof, and each side wall of thepair of side walls of the channel section preferably has a uniformthickness along a length thereof.

Desirably, at least a proximal end of the channel section is fixedlysecured to a proximal end of the channel member.

It is envisioned that the deflection control system can be a multi-stagesystem, e.g., a two-stage system, a three-stage system, a four-stagesystem, etc. In a two-stage system, the deflection control system beginsreducing the rate of deflection of the distal end of the channel memberin a second stage of deflection. The second stage of deflectiondesirably takes effect when the reveal between the side walls of thechannel member and the side walls of the channel section is about zero.Accordingly, the distal end of the channel member and the distal end ofthe channel section deflect concomitantly.

The deflection control system functions such that the greater the rateof deflection of the distal end of the channel member, the greater thereduction in the rate at which the distal end of the channel sectiondeflects. It is contemplated that the reveal between the distal end ofthe channel member and the distal end of the channel section can bezero.

According to another embodiment of the present disclosure, thedeflection control system can include a first U-shaped channel sectionhaving a pair of side walls interconnected by a base wall, wherein thebase wall of the first channel section of the deflection control systemis adjacent to or, more preferably in contact with the base wall of thechannel member of the anvil half-section, and a second U-shaped channelsection having a pair of side walls interconnected by a base wall,wherein the base wall of the second channel section of the deflectioncontrol system is adjacent to or, more preferably in contact with thebase wall of the first channel section of the deflection control system.

A distal end of each side wall of the pair of side walls of the firstchannel section can have a height which is less than a height of arespective side wall of the pair of side walls of the channel memberthereby defining a first reveal along each of the pair of side walls ofthe channel member. In addition, each side wall of the pair of sidewalls of the second channel section can have a height which is less thana height of the respective side walls of the pair of side walls of thefirst channel section thereby defining a second reveal along a distalend of each side wall of the pair of side walls of the second channelsection.

A proximal end of each of the first and second channel sections can beoperatively fixedly secured to a proximal end the channel member. It iscontemplated that the height of the distal end of each side wall of thepair of side walls of the first channel section and the height of acorresponding distal end of each side wall of the pair of side walls ofthe second channel section are uniform along each of the lengthsthereof.

In this embodiment the deflection control system is a three-stagesystem. In a three-stage system the deflection control system beginsreducing the rate of deflection of the distal end of the channel sectionin a second stage of deflection, and in a third stage of deflection thedeflection control system reduces the rate of deflection of the distalend of the channel member by an additional amount. In operation, thesecond stage of deflection engages when the first reveal between theside walls of the channel member and the side walls of the first channelsection is about zero, whereby the distal end of the channel member andthe distal end of the first channel section deflect concomitantly. Thethird stage of deflection engages when the second reveal between theside walls of the first channel section and the side walls of the secondchannel section is about zero, whereby the distal end of the channelmember, the distal end of the first channel section and the distal endof the second channel section deflect concomitantly.

According to another embodiment the deflection control system includes apair of reinforcing ribs each disposed along an inner surface of arespective side wall of the pair of side walls of the channel member.Each rib of the pair of reinforcing ribs of the deflection controlsystem has a height which is less than the height of the respective sidewalls of the channel member thereby defining a reveal along each of thepair of side walls of the channel member. It is envisioned that aproximal end of each of the pair of reinforcing ribs is pinned to aportion of the proximal end of the channel member.

In another embodiment, a proximal end of the deflection control systemis fixedly secured to a portion of the proximal end of the channelmember and a portion of the distal end of the deflection control systemis longitudinally slidingly coupled to the channel member. Thedeflection control system can include at least one, preferably aplurality of, reinforcing plate(s) adjacent, preferably in contact withthe base wall of the channel member.

In this embodiment, the surgical fastener applying apparatus can furtherinclude a pin member fixedly secured to the base wall of the channelmember. The distal end of each of the plurality of reinforcing plates isslidingly coupled to the channel member by the pin member extendingthrough a plurality of elongate longitudinally oriented slots formed,one each, in the plurality of respective reinforcing plates. Theelongate slots preferably increase in length from the reinforcing platewhich is closest to the base wall of the channel member to thereinforcing plate which is furthest from the base wall of the channelmember. The slots of the plates each have a proximal edge, and desirablythe proximal edges are in registration with one another. The pin memberdesirably includes a head secured to an end thereof that is opposite tothe base wall. The head engages the reinforcement plates and forces thedistal end of each of the reinforcing plates to deflect concomitantlywith the distal end of channel member.

In operation, as the distal end of the channel member and the deflectioncontrol system deflect in a direction transverse to the longitudinalaxis, the distal end of at least one of the plurality of reinforcingplates translates in a longitudinal direction. The deflection controlsystem is a multi-stage system which begins to incrementally reduce therate of deflection of the distal end of the channel member as a distalend of each elongate slot of each respective reinforcing plate engagesthe pin member. The deflection control system incrementally reduces therate at which the distal end of the channel member deflects.

In another embodiment, surgical fastener applying apparatus can beprovided with a pair of juxtaposed shoulders each extending from aninner surface of the side walls of the channel member in a distal endthereof. Each reinforcing plate can include an elongate recesses formedalong each lateral side thereof and in operative engagement with arespective one of the pair of shoulders. The elongate recessespreferably increase in length from the reinforcing plate which isclosest to the base wall of the channel member to the reinforcing platewhich is furthest from the base wall of the channel member. Each of theelongate recesses has a proximal edge and wherein the proximal edges arein registration with one another. Each shoulder preferably includes ahead portion secured to an end thereof, the head portion beingconfigured and dimensioned to force the distal end of each of thereinforcing plates to deflect concomitantly with the distal end ofchannel member.

In operation, as the distal end of the channel member and the deflectionsystem deflect in a direction transverse to the longitudinal axis thedistal end of each of the plurality of reinforcing plates translates ina longitudinal direction. The deflection control system is a multi-stagesystem, wherein the deflection control system begins to incrementallyreduce the rate of deflection of the distal end of the channel member asa distal end of each elongate recess of each respective reinforcingplate engages a respective shoulder, the deflection control systemincrementally reduces the rate at which the distal end of the channelmember deflects.

According to another aspect of the present disclosure, a deflectioncontrol system is provided for a surgical fastener applying apparatusthat includes an anvil half-section having a channel member and acartridge receiving half-section operatively couplable to the anvilhalf-section. The deflection control system includes an elongatereinforcing assembly having a proximal end operatively engaged with aproximal end of the channel member and a distal end operativelyassociated with a distal end of the channel member, wherein thereinforcing assembly incrementally reduces deflection of the distal endof the channel member when forces are applied to the distal end of thechannel member in a direction transverse to a longitudinal axis of thechannel member and normal to a tissue contacting surface of the anvilhalf-section.

According to another aspect of the present disclosure, a surgicalfastener applying apparatus is provided. It includes an anvilhalf-section including a distal end and a proximal end defining alongitudinal axis, the anvil half-section including a channel memberhaving pair of juxtaposed side walls interconnected by a base wall, eachside wall defining a through hole having a diameter. The apparatusfurther includes a cartridge receiving half-section including a distalend, wherein the cartridge receiving half-section is couplable with theanvil half-section such that the distal end of the anvil half-section ismovable into juxtaposed relation to the distal end of the cartridgereceiving half-section. The distal ends of the anvil and cartridgehalf-sections can be pivotable about a pivot axis transverse to thelongitudinal axis.

The surgical fastener applying apparatus further includes a deflectioncontrol system operatively associated with the anvil half-section forreinforcing the distal end of the anvil half-section when a force isapplied to the distal end of the anvil half-section in a directiontransverse to the longitudinal axis. The deflection control system mostpreferably includes a pair of reinforcing ribs having a distal end and aproximal end. The distal end of each reinforcing rib is fixedly securedto an inner surface of a respective side wall of the pair of side wallsof the channel member and the proximal end of each reinforcing ribextends beyond the pivot axis. The proximal end of each reinforcing ribdefines a hole in registration with the through hole defined in the sidewalls of the channel member. The holes are desirably positioned proximalof the pivot axis. The deflection control system further includes a cammember extending through the holes formed in each side wall of thechannel member and each reinforcing rib, the cam having a diametersmaller than the diameter of the through hole formed in each reinforcingrib to thereby define a reveal between each reinforcing rib and the cammember.

This deflection control system is a two-stage system. Accordingly, inoperation, the deflection control system begins reducing the degree andthe rate of deflection of the distal end of the channel member in asecond stage of deflection. The second stage of deflection takes effectwhen the reveal between an upper portion of the hole formed in eachreinforcing rib and an upper portion of the cam is zero.

Further features of the disclosure, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example only, preferred embodiments of the present disclosurewill be described herein with reference to the accompanying drawings, inwhich:

FIG. 1 is a perspective view of a surgical fastener applying apparatusin accordance with the present disclosure;

FIG. 2 is a side elevational view showing the distal end of the surgicalfastener applying apparatus of FIG. 1;

FIG. 3 is a top perspective view, with parts separated, of an anvilhalf-section of the surgical fastener applying apparatus of FIG. 1;

FIG. 4 is a bottom perspective view of an anvil half-section channelmember of the anvil half-section of FIG. 3;

FIG. 5 is a transverse cross-sectional view of a portion of the distalend of the channel member of FIG. 4, as taken along section line 5-5 ofFIG. 4;

FIG. 6 is a transverse cross-sectional view of a portion of the distalend of a channel member, in accordance with an alternative embodiment ofthe present disclosure, as would be seen along section line 5-5 of FIG.4;

FIG. 7 is a bottom perspective view, with parts separated, of the distalend of an anvil half-section, in accordance with another embodiment ofthe present disclosure;

FIG. 8 is a transverse cross-sectional view of a portion of the distalend of a channel member of the assembled parts of the anvil half sectionof FIG. 8, as would be seen along section line 8-8 of FIG. 7;

FIG. 9 is a longitudinal cross-sectional view of a portion of the distalend of the channel member of FIGS. 7 and 8 when no load is applied to adistal end thereof;

FIG. 10 is a longitudinal cross-sectional view of a portion of thedistal end of the channel member of FIG. 9 having a load applied to adistal end thereof;

FIG. 11 is a longitudinal cross-sectional view of the distal end of ananvil half-section of a channel member in accordance with yet anotheralternative embodiment of the present disclosure;

FIG. 12 is a transverse cross-sectional view of a portion of the distalend of the channel member of FIG. 11, as would be seen along line 12-12of FIG. 11;

FIG. 13 is a bottom plan view of a portion of the distal end of thechannel member of FIGS. 11 and 12;

FIG. 14 is a longitudinal cross-sectional view of a portion of thedistal end of a channel member of an anvil half-section in accordancewith yet another alternative embodiment of the present disclosure;

FIG. 15 is a transverse cross-sectional view of a distal end portion ofthe channel member of FIG. 14, as would be seen along line 15-15 of FIG.14;

FIG. 16 is a top plan view of a portion of the distal end of the channelmember of FIGS. 14 and 15;

FIG. 17 is a graph illustrating the effects of the use of a deflectioncontrol system, in accordance with the present disclosure, in an anvilhalf-section;

FIG. 18 is a bottom perspective view of a portion of the distal end of achannel member of an anvil half-section, in accordance with anotherembodiment of the present disclosure;

FIG. 19 is a transverse cross-sectional view of the channel member ofFIG. 18, as would be seen along line 19-19 of FIG. 18;

FIG. 20 is a bottom plan view of the distal end of the channel member ofFIG. 18;

FIG. 21 is a longitudinal cross-sectional view of a portion of thedistal end of the channel member of FIGS. 18 and 19, as would be seenalong section line 21-21 of FIG. 20;

FIG. 22 is an enlarged view of the area indicated 22 of FIG. 21; and

FIG. 23 is an enlarged view of the area indicated 23 of FIG. 21.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the presently disclosed surgical fastenerapplying apparatus will now be described in detail with reference to thedrawing figures wherein like reference numerals identify similar oridentical elements. In the drawings and in the description whichfollows, the term “proximal” will refer to the end of the surgicalfastener applying apparatus which is closest to the operator, while theterm “distal” will refer to the end of the surgical fastener applyingapparatus which is furthest from the operator.

Referring to FIGS. 1-5, a surgical fastener applying apparatus, inaccordance with the present disclosure, is shown generally as 100.Apparatus 100 is particularly adapted to apply surgical staples andincludes a cartridge receiving half-section 102, an anvil half-section104 operatively coupled to cartridge receiving half-section 102, astaple cartridge assembly 106 fixedly or removably supported in a distalend 102 a of cartridge receiving half-section 102 and an anvil plate 108fixedly or removably supported on a distal end 104 a of anvilhalf-section 104.

For purposes of illustration, the present disclosure describes beamdeflection control systems with specific reference to a surgicalfastener applying apparatus, preferably a surgical stapler. It isenvisioned, however, that the beam deflection control system andillustrative embodiments herein may be incorporated in any surgicalfastener applying apparatus having at least one cantilevered beam memberwhich may be subject to deflection under an applied load which has aforce component transverse to the longitudinal axis of the beam. It isfurther envisioned that the beam deflection control system andillustrative embodiments disclosed herein may be incorporated intoand/or equally applied to endoscopic, laparoscopic as well as open typesurgical instruments. The “beam” referred to in “beam deflection controlsystem” can be distal end 102 a of cartridge half-section 102, and/ordistal end 104 a of anvil half-section 104, although most of thediscussion herein will refer to the distal end of the anvil half-sectionbecause, of the two, typically it is the member which deflects the most.

As seen in FIG. 2, when anvil half-section 104 is operatively coupled tocartridge receiving half-section 102, a tissue gap “G” exists betweendistal end 104 a of anvil half-section 104 and distal end 102 a ofcartridge receiving half-section 102. Tissue gap “G” is typically set toa predetermined dimension during the manufacture of surgical staplingapparatus 100 to allow for desired staple formation. Preferably, tissuegap “G” is tapered, i.e., narrower adjacent a distal end of apparatus100 than at a location proximal of the distal end of apparatus 100. Asdescribed above with regard to previous surgical fastener applyingapparatus, when distal ends 104 a of anvil half-section 104 and distalend 102 a of cartridge receiving half-section 102 are clamped ontotissue, a deflection force is exerted thereon, in the directionsindicated by arrows “Y” (i.e., in directions transverse to thelongitudinal axis of the surgical fastener applying apparatus), tendingto cause distal end 104 a of anvil half-section 104 and/or distal end102 a of cartridge receiving half-section 102 to deflect, e.g., in thedirection of arrows “Y”. As is known in the art, the degree ofdeflection of distal ends 104 a, 102 a of anvil half-section 104 andcartridge receiving half-section 102 tend to increase at locations or inportions increasingly closer to the distal tips thereof. As is alsoknown in the art, the thicker the tissue to be clamped the greater thedeflection force exerted. Also, tissue thickness can vary, e.g.,increase, during approximation and stapling. This can be due, e.g., totissue fluid flow typically toward the distal tip of the apparatusduring approximation of distal ends 104 a, 102 a of anvil and cartridgereceiving half-sections 104, 102, especially those that are pivotablymounted.

Thus, the greater the degree of deflection in the direction of arrows“Y”, the greater the likelihood that the dimension of the distal end oftissue gap “G” may vary from its predetermined setting. As a result, itmay occur that staples (not shown) fired from staple cartridge assembly106 may form non-uniformly along the length of anvil plate 108. In theregion where the dimension of tissue gap “G” remains or is close to thepredetermined setting, i.e., near intermediate point 112 c (FIG. 3) thelegs of the staples will form as intended. However, it may occur that ifexcessively thick over-indicated tissue is inadvertently fastened, thedimension of tissue gap “G” may increase beyond its predeterminedsetting, e.g., near the distal tip of anvil plate 108, and there is apossibility that in that area the legs of the staples may not form asdesired. The purpose of this disclosure is to reduce the possibility ofor prevent this from occurring. Elsewise stated, the purpose of thisdisclosure is to increase the possibility that even if excessively thickover-indicated tissue is encountered, deflection will be minimized orprevented, to enhance the possibility of and provide for acceptablestaple formation.

As seen in FIG. 3, anvil half-section 104 includes an anvil half-sectionchannel member 112 having a distal end 112 a, a proximal end 112 b and atransition or intermediate point 112 c. Channel member 112 has asubstantially U-shaped transverse cross-sectional profile defined by apair of substantially parallel juxtaposed side walls 114 interconnectedby a base wall 116.

Anvil plate 108 is preferably configured and dimensioned to fit overside walls 114 of distal end 112 a of channel member 112. As seen inFIG. 3, anvil plate 108 includes a pair of tissue contacting surfaces118 each having a plurality of staple forming pockets 120 (i.e., anvilpockets, anvil depressions, etc.) formed therein. Preferably, anvilplate 108 includes a knife track 122 extending longitudinally betweenthe pair of tissue contacting surfaces 118. Preferably, knife track 122interconnects and separates the pair of tissue contacting surfaces 118from one another. Anvil plate 108 further includes a pair ofsubstantially parallel juxtaposed upstanding side walls 124 extending,one each, from a lateral side edge of the pair of anvil surfaces 118.

Anvil half-section 104 further includes a distal end cap 126 adapted tobe snap-fit onto or into the distal tip of channel member 112.Preferably, end cap 126 is tapered to facilitate insertion of the distaltip into the target surgical site. Anvil half-section 104 can alsoinclude an end cap 128 to be received between a pair of spaced apartjuxtaposed flanges 130 (one shown) extending from proximal end 112 b ofchannel member 112.

Anvil half-section 104 can further include a contoured hand grip 132configured and adapted to be snap-fit over proximal end 112 b of channelmember 112. Hand grip 132 desirably provides an operator of surgicalstapling apparatus 100 with improved control and an increased degree ofmanipulation.

As seen in FIGS. 3-5, anvil half-section 104 includes a deflectioncontrol system, generally designated 140 for reducing the rate ofdeflection of distal end 112 a of channel member 112 as the force indirection “Y” increases and as the deflection distance of distal end 112a of channel member 112 increases. In this embodiment, deflectioncontrol system 140 includes a substantially U-shaped channel section 142disposed between side walls 114 of channel member 112. As best seen inFIG. 5, channel section 142 is defined by a pair of parallel spacedapart juxtaposed side walls 144 interconnected by a base wall 146. Inparticular, side walls 144 of channel section 142 preferably have aheight which is less than a height of side walls 114 of channel member112 thus defining a reveal 150 having a height “X”.

Height “X” of reveal 150 can be uniform or vary along the entire lengthof distal end 112 a of channel member 112 and distal end 142 a ofchannel section 142. Although, height “X” can taper in either a distalor a proximal direction, preferably it tapers in a distal direction,e.g., from being narrow or zero near the distal tip to a greater heightnear transition point 112 c. Reveal 150 can have discrete regions orlengths, each of which, has a different height “X”. Preferably, height“X” is from about 0.004 inches to about 0.10 inches, more preferablyfrom about 0.004 inches to about 0.006 inches. As will be described ingreater detail below, when height “X” is about 0.004 inches to about0.006 inches, distal end 104 a of anvil half-section 104 becomes stiffersooner as compared to when height “X” is greater than 0.006 inches.

Channel section 142 extends from distal end 112 a of channel member 112to a portion of proximal end 112 b. Channel section 142 is fixedlysecured to channel member 112 preferably at least in a region proximalof but adjacent intermediate point 112 c to allow channel section 142 tobe free to float within channel member 112 in a region distal ofintermediate point 112 c (i.e., distal end 112 a).

It is envisioned that channel section 142 can be secured at suchlocations to channel member 112 at suitable specific predeterminedlocations along the length thereof. In particular, side walls 144 ofchannel section 142 can be secured to corresponding side walls 114 ofchannel member 112, and base wall 146 of channel section 142 can besecured to base wall 116 of channel member 112.

Channel section 142 is preferably secured to channel member 112 bypinning (i.e., by extending a pin through channel section 142 and intoan adjacent element or structure of apparatus 100), however, it isenvisioned that channel section 142 can be secured to channel member 112via any number of known techniques, such as, for example, welding,soldering, gluing, peening and the like. Most preferably, channelsection 142 is, as will be explained, welded to channel member 112 and acam 400 can extend through side walls 144 of channel section 142 to pinchannel section 142 to side walls 144.

Channel section 142 is made from a rigid material which is resistant tobending, such as, for example, steel. While steel is preferred, it iscontemplated that channel section 142 can be fabricated from othermaterials, such as, for example, titanium, polycarbonate, fiberglass,resins and the like, or any combination thereof.

It is further contemplated that each side wall 144 of channel section142 have a pre-selected thickness. A relatively smaller thicknessprovides less rigidity while a relatively larger thickness providesincreased rigidity. It is still further contemplated that each side wall144 can have a uniform or varying thickness along its length.

In operation, channel section 142 increases the rigidity of channelmember 112 (i.e., reduces the rate of deflection) after channel member112 has undergone a predetermined amount of deflection in direction “Y”(e.g., transverse to a longitudinal axis of apparatus 100 andsubstantially normal to the plane of the tissue contacting surface ofanvil 108) thereby reducing the rate of deflection of distal end 112 aof channel member 112. As will be used herein, the recitation “tissuehaving a relatively smaller thickness” is understood to mean tissuehaving a thickness which will not tend to cause distal end 104 a ofanvil half-section 104 to deflect an amount sufficient to result in theoperation of deflection control system 140. Also, the recitation “tissuehaving a relatively larger thickness” is understood to mean tissuehaving a thickness which will tend to cause distal end 104 a of anvilhalf-section 104 to deflect an amount sufficient to result in theoperation of deflection control system 140.

Surgical stapling apparatus 100 preferably is initially set-up such thattissue gap “G” has a slight taper from a proximal end to a distal end(i.e., tissue gap “G” reduces in height from the proximal end to thedistal end). In this manner, when tissue having a relatively smallerthickness is clamped between the distal ends 104 a, 102 a of anvilhalf-section 104 and cartridge receiving half-section 102, the distalends 104 a, 102 a of anvil half-section 104 and/or cartridge receivinghalf-section 102 will deflect an amount sufficient to cause tissue gap“G” to have a substantially uniform dimension from proximal end todistal end. As such, the staples which are fired from staple cartridgeassembly 106 are substantially uniformly formed from the proximal end ofstaple cartridge assembly 106 to the distal end of staple cartridgeassembly 106.

When tissue having a relatively larger thickness is clamped betweendistal ends 104 a, 102 a of anvil half-section 104 and cartridgereceiving half-section 102, channel section 142 of deflection controlsystem 140 causes distal end 104 a of anvil half-section 104 to undergoa two-stage deflection. In the first stage of deflection the deflectionforce acts solely on edge surfaces 114 a of side walls 114, oriented inthe direction of the tissue to be clamped, of channel member 112resulting in distal end 104 a of anvil half-section 104 undergoing aninitial rate of deflection in direction “Y”, until height “X” of reveal150, between side walls 144 of channel section 142 and side walls 114 ofchannel member 112, is reduced to zero (i.e., the height of side walls144 of channel section 142 are even with the height of side walls 114 ofchannel member 112).

Edge surfaces 114 a can be in direct contact with the tissue or, morepreferably they are oriented in the direction of the tissue and arerather in direct contact with undersurface of tissue contacting surfaces118 of anvil plate 108 which in turn are in contact with the tissue.

In addition, during the first stage of deflection, the height of tissuegap “G” is urged from its initial tapered configuration to a secondconfiguration which is less tapered (i.e., less angled). At this point,edge surfaces 144 a of side walls 144 of channel section 142 and edgesurfaces 114 a of side walls 114 of channel member 112 are in contactwith the underside of tissue contacting surfaces 118 of anvil plate 108thereby making distal end 104 a of anvil half-section 104 stiffer and/ormore rigid thus reducing the tendency of distal end 104 a of anvilhalf-section 104 to deflect.

Once height “X” of reveal 150 reaches zero, each edge surface 114 a, 144a of side walls 114 and 144, respectively, is in contact with theunderside of tissue contacting surfaces 118 of anvil plate 108 anddistal end 104 a of anvil half-section 104 and undergoes a second stageof deflection. In other words, the deflecting force now acts on sidewalls 114 and 144 in order to urge and deflect distal end 104 a of anvilhalf-section 104. Since the deflecting force must now act on both sidewalls 114 and 144, distal end 104 a of anvil half-section 104 iseffectively reinforced and stiffened from this time forward.

In the second stage, deflection control system 140 causes distal end 104a of anvil half-section 104 to undergo a rate of deflection which isless than the initial rate of deflection. In addition, during the secondstage of deflection, the height of tissue gap “G” is urged from itstapered configuration to a configuration that is less tapered or has asubstantially uniform dimension (i.e., uniform height) from the distalend to the proximal end. Deflection control system 140 in effectprevents the distal end of tissue gap “G” from having a reverse taperedconfiguration (i.e., the distal end having a larger height than theproximal end).

Turning now to FIG. 6, a deflection control system, for controllingand/or incrementally reducing the rate of deflection of distal end 112 aof channel member 112, in accordance with an alternative embodiment ofthe present disclosure, is shown generally as 240. Deflection controlsystem 240 is a dual layered substantially U-shaped channel section 242configured and dimensioned to be disposed in and between side walls 114of channel member 112. Channel section 242 includes an outer channelsection 242 a and an inner channel section 242 b. Outer channel section242 a is defined by a pair of parallel spaced apart juxtaposed sidewalls 244 a interconnected by a base wall 246 a. In particular, sidewalls 244 a of channel section 242 a preferably have a height which isless than a height of side walls 114 of channel member 112 thus defininga first reveal 250 a.

Inner channel section 242 b is defined by a pair of parallel spacedapart juxtaposed side walls 244 b interconnected by a base wall 246 b.In particular, side walls 244 b of channel section 242 b preferably havea height which is less than a height of side walls 244 a of channelsection 242 a thus defining a second reveal 250 b. Preferably, innerchannel section 242 b is pinned by a cam member (not shown) nearintersecting point 112 c, secured to outer channel section 242 a at aregion proximal of intermediate point 112 c and is secured at a regionnear the distal tip (see FIG. 4). Inner channel section 242 b islikewise preferably secured to outer channel section 242 a via pinningor in any manner as described above with regard to channel section 142of FIGS. 3-5.

When tissue having a relatively smaller thickness is clamped betweendistal ends 104 a, 102 a of anvil half-section 104 and cartridgereceiving half-section 102 deflection control system 240 functionsbasically the same manner as deflection control system 140. When tissuehaving a relatively larger thickness is clamped between distal ends 104a, 102 a of anvil half-section 104 and cartridge receiving half-section102, channel section 242 of deflection control system 240 causes distalend 104 a of anvil half-section 104 to undergo a three-stage deflection.In the first stage of deflection the deflection force acts solely onedge surfaces 114 a of side walls 114 of channel member 112 resulting indistal end 104 a of anvil half-section 104 undergoing an initial rate ofdeflection in direction “Y” until height “X” of reveal 250 a, betweenside walls 244 a of outer channel section 242 a and side walls 114 ofchannel member 112 is reduced to zero (i.e., the height of side walls244 a of outer channel section 242 a are even with the height of sidewalls 114 of channel member 112). At this point, edge surfaces 114 a and245 a of respective side walls 114 and 244 a are each in contact withthe underside of tissue contacting surfaces 118 of anvil plate 108thereby making distal end 104 a of anvil half-section 104 stiffer and/ormore rigid thus reducing its tendency to deflect.

Once reveal 250 a reaches zero, each edge surface 114 a, 245 a of sidewalls 114 and 244 a, respectively, is in contact with the underside oftissue contacting surfaces 118 of anvil plate 108 and distal end 104 aof anvil half-section 104 undergoes a second stage of deflection. Sincethe deflecting force must now act on side walls 114 and 244 a, distalend 104 a of anvil half-section 104 is effectively reinforced andstiffened from this time forward. In the second stage, channel section242 of deflection control system 240 causes distal end 104 a of anvilhalf-section 104 to undergo a second degree of deflection which is lessthan the initial degree of deflection at a second rate of deflectionwhich is less than the initial rate of deflection.

During the second stage of deflection, distal end 104 a of anvilhalf-section 104 and outer channel section 242 a deflect, in direction“Y”, until reveal 250 b between side walls 244 b of inner channelsection 242 b and side walls 244 a of outer channel section 242 a isreduced to zero. At this point, edge surfaces 114 a, 245 a and 245 b ofrespective side walls 114, 244 a and 244 b are in contact with theunderside of tissue contacting surfaces 118 of anvil plate 108 therebymaking distal end 104 a of anvil half-section 104 still more stifferand/or still more rigid thus further reducing the tendency of distal end104 a of anvil half-section 104 to deflect.

Once reveal 250 b reaches zero, each edge surface 114 a, 245 a and 245 bof side walls 114, 244 a and 244 b, respectively, is in contact with theunderside of tissue contacting surfaces 118 of anvil plate 108 anddistal end 104 a of anvil half-section 104 undergoes a third stage ofdeflection. Since the deflecting force must now act on side walls 114,244 a and 244 b, distal end 104 a of anvil half-section 104 iseffectively further reinforced and stiffened from this time forward.

Channel sections 242 a and 242 b are each preferably made from a rigidmaterial, such as for example, steel. While steel is preferred, it iscontemplated that each of channel section 242 a and 242 b can each befabricated from other materials, such as, for example, titanium,polycarbonate, fiber glass, resins and the like or any combinationthereof.

Side walls 244 a of outer channel section 242 a and side walls 244 b ofinner channel section 242 b each preferably have a uniform height alongtheir respective lengths. However, it is contemplated that side walls244 a of outer channel section 242 a and side walls 244 b of innerchannel section 242 b can have varying heights along their lengths.Preferably, side walls 244 a of outer channel section 242 a and sidewalls 244 b of inner channel section 242 b each have a uniformthickness, however, it is envisioned that they can have varyingthicknesses along their lengths. The height and thickness of each sidewall 244 a of outer channel section 242 a and of each side wall 244 b ofinner channel section 242 b is specifically selected depending on thedegree of stiffness desired and on which regions of anvil half-section104 are desired to be stiffened.

Turning now to FIGS. 7-10, a deflection control system, for controllingand/or reducing the rate of deflection of distal end 112 a of channelmember 112, in accordance with a preferred embodiment of the presentdisclosure is shown generally as 340. Deflection control system 340includes a pair of parallel spaced apart juxtaposed reinforcing platesand/or ribs 344, each one to be secured to a respective side wall 114 ofchannel member 112.

Each reinforcing rib 344 is preferably secured to a respective side wall114 of channel member 112 at a region proximal of intermediate point 112c (See FIG. 4). Preferably, each reinforcing rib 344 is secured to itsrespective side wall 114 by being welded or pinned at a locationproximal of intermediate point 112 c. Other methods of securingreinforcing ribs 344 to side walls 114 are contemplated, such as, forexample, gluing, adhering, peening and the like. Each reinforcing rib344 is preferably made from stainless steel and has a uniform height andthickness. In particular, reinforcing ribs 344 preferably have a heightwhich is less than a height of side walls 114 of channel member 112 thusdefining a reveal 350.

When tissue having a relatively smaller thickness is clamped betweendistal ends 104 a, 102 a of anvil half-section 104 and cartridgereceiving half-section 102, deflection control system 340 functions inthe same manner as described above for control system 140. As seen inFIGS. 9 and 10, when tissue having a relatively larger thickness isclamped between distal ends 104 a, 102 a of anvil half-section 104 andcartridge receiving half-section 102, reinforcing ribs 344 of deflectioncontrol system 340 causes distal end 104 a of anvil half-section 104 toundergo a two-stage deflection. In the first stage of deflection thedeflection force acts solely on edge surfaces 114 a of side walls 114 ofchannel member 112 resulting in distal end 104 a of anvil half-section104 undergoing an initial rate of deflection in direction “Y” untilreveal 350 between reinforcing ribs 344 and side walls 114 of channelmember 112 is reduced to zero (i.e., the height or edges of reinforcingribs 344 are even with the height or edges of side walls 114 of channelsection 112).

During the first stage of deflection, the height of tissue gap “G” isurged from its initial tapered configuration to a second configurationwhich is less tapered (i.e., less angled) than the initial taperedconfiguration or substantially uniform. At this point, edge surfaces 114a of side walls 114 and edge surfaces 344 a of reinforcing rib 344 arein contact with the underside of tissue contacting surfaces 118 of anvilplate 108 thereby making distal end 104 a of anvil half-section 104stiffer and/or more rigid thus reducing the tendency of distal end 104 aof anvil half-section 104 to deflect. Once reveal 350 reaches zero, eachedge surface 114 a, 344 a of side walls 114 and of reinforcing rib 344,respectively, are in contact with the underside of tissue contactingsurfaces 118 of anvil plate 108 and distal end 104 a of anvilhalf-section 104 undergoes a second stage of deflection.

In the second stage, deflection control system 340 causes distal end 104a of the anvil half-section 104 to undergo a rate of deflection which isless than the initial rate of deflection. In addition, during the secondstage of deflection the height of tissue gap “G” is urged from itssecond less tapered configuration to a configuration having asubstantially uniform dimension (i.e., uniform height) from the distalend to the proximal end. Deflection control system 340 in effectprevents the distal end of tissue gap “G” from having a reverse taperedconfiguration (i.e., the distal end having a larger height than theproximal end).

Turning now to FIGS. 11-13, a deflection control system, for controllingand/or incrementally reducing the rate of deflection of distal end 112 aof channel member 112, in accordance with yet another embodiment of thepresent disclosure is shown generally as 460 (see FIG. 12). Deflectioncontrol system 460 is generally in the form of a leaf-spring andincludes a layered reinforcing member 462 (see FIG. 12) having aplurality of individual reinforcing plates (e.g., 462 a, 462 b and 462c) extending longitudinally between side walls 114 of channel member 112and resting atop base wall 116. While deflection control system 460 isshown as having three reinforcing members, it is envisioned thatdeflection control system 460 can have any number of reinforcingmembers, including, and not limited to, one, two, four, etc.

Deflection control system 460 further includes a pin member 468extending through a series of elongate slots 470 formed in reinforcingmember 462. Preferably, a proximal end 464 of reinforcing member 462 isfixedly secured to channel member 112, by means of welding, riveting andthe like, at a location proximal of intermediate portion 112 c while adistal end 466 of reinforcing member 462 is preferably slidably securedto distal end 112 a by pin member 468. Distal end 466 of reinforcingmember 462 is preferably pinned at a location proximate to thedistal-most edge 112 d of channel member 112. Pin member 468 includes abody portion 472 having a first end 474 fixedly secured to base wall 116of channel member 112 and a second end 476 extending through reinforcingmember 462, and an enlarged head 478 secured to second end 476. Head 478is configured and dimensioned to be larger than elongate slots 470 andto rest on the upper-most reinforcing plate. Body portion 472 of pinmember 468 is dimensioned such that head 478 maintains reinforcingplates 462 a-462 c in sliding contact with one another. While it ispreferred that pin member 468 extend through base wall 116 of channelmember 112 it is envisioned that pin member 468 can extend through sidewalls 114 of channel member 112 at a location to engage reinforcingmember 462.

Reinforcing member 462 includes a first reinforcing plate 462 a having afirst elongate slot 470 a formed therein and extending in a longitudinaldirection, wherein first elongate slot 470 a has a first length.Reinforcing member 462 further includes a second reinforcing plate 462 bhaving a second elongate slot 470 b formed therein and extending in alongitudinal direction, wherein second elongate slot 470 b has a secondlength which is greater than the first length of first elongate slot 470a. Reinforcing member 462 further includes a third reinforcing plate 462c having a third elongate slot 470 c formed therein and extending in alongitudinal direction, wherein third elongate slot 470 c has a thirdlength which is greater than the second length of second elongate slot470 b.

In operation, reinforcing member 462 increases the rigidity of channelmember 112 only after channel member 112 has undergone a predeterminedamount of deflection in direction “Y”, to thereby reduce the rate ofdeflection of distal end 112 a of channel member 112. Accordingly, whentissue having a relatively small thickness is clamped between distalends 104 a, 102 a of anvil half-section 104 and cartridge receivinghalf-section, distal end 104 a of anvil half-section 104 will tend todeflect an amount sufficient for tissue gap “G” to have a substantiallyuniform dimension from the proximal end to the distal end thereof.

When tissue having a relatively larger thickness is clamped betweendistal ends 104 a, 102 a of anvil half-section 104 and cartridgereceiving half-section 102, deflection control system 460 causes distalend 104 a of anvil half-section 104 to undergo a four-stage deflection.In a first stage of deflection, distal end 112 a of channel member 112undergoes an initial rate of deflection, in direction “Y”, until thedistal surface of first slot 470 a of first reinforcement plate 462 acontacts pin member 468 thus beginning a second stage of deflection.

In the second stage of deflection, distal end 112 a of channel member112 and first reinforcement plate 462 a undergo a second rate ofdeflection, in direction “Y”, until the distal surface of second slot470 b of second reinforcement plate 462 b contacts pin member 468, thusbeginning a third stage of deflection. Since the deflection force is nowacting on distal end 112 a of channel member 112 of anvil half-section104 and on first reinforcement plate 462 a, the second rate ofdeflection is less than the first rate of deflection.

In the third stage of deflection, distal end 112 a of channel member 112and both first and second reinforcement plates 462 a and 462 b undergo athird rate of deflection, in direction “Y”, until the distal surface ofthird slot 470 c of third reinforcement plate 462 c contacts pin member468, thus beginning a fourth stage of deflection. Since the deflectionforce is now acting on distal end 112 a of channel member 112 and bothfirst and second reinforcement plates 462 a and 462 b, the third rate ofdeflection is less than the second rate of deflection.

In the fourth stage of deflection, distal end 112 a of channel member112 and each of first, second and third reinforcement plates 462 a-462 cundergo a fourth rate of deflection, in direction “Y”. Since thedeflection force is now acting on distal end 112 a of channel member 112and on each of first, second and third reinforcement plates 462 a-462 c,the fourth rate of deflection is less than the third rate of deflection.

At each stage of deflection, distal end 112 a of channel member 112 isfurther stiffened by the interaction of deflection control system 460with distal end 112 a of channel member 112. Deflection control system460 will permit distal end 112 a to deflect an initial amount, indirection “Y”, in a manner similar to if deflection control system 460was not provided. However, when the deflection, in direction “Y”,becomes greater than a predetermined amount, deflection control system460 is engaged and distal end 112 a of channel member 112 is stiffened.As described above, deflection control system 460 can provide distal end112 a of channel member 112 with multiple stages of incrementalstiffening, however, it is within the scope of the present disclosurethat deflection control system 460 provides distal end 112 a of channelmember 112 with a single stage of stiffening.

Turning now to FIGS. 14-16, a deflection control system, for controllingand/or incrementally reducing the rate of deflection of distal end 112 aof channel member 112, in accordance with still another embodiment ofthe present disclosure is shown generally as 560. Deflection controlsystem 560 is generally in the form of a leaf-spring and includes alayered reinforcing member 562 having a plurality of individualreinforcing plates (e.g., 562 a, 562 b and 562 c) extendinglongitudinally between side walls 114 of channel member 112 and restingatop base wall 116.

Deflection control system 560 further includes a pair of juxtaposedshoulders 580 preferably integrally formed with and extendingtransversely from an inner surface of side walls 114 of channel member112. While a pair of integral shoulders 580 are shown, it iscontemplated that shoulders 580 can be formed from elements (i.e.,bolts, screws, pins, brackets, etc.) extending through side walls 114.Each shoulder 580 includes a body portion 582 having a height greaterthan reinforcing member 562 and a head portion 584 configured anddimensioned to overlie reinforcing member 562.

Body portion 582 of shoulders 580 preferably extends into a series ofelongate recesses 590 formed along the lateral sides of reinforcingmember 562. Preferably, a proximal end of 564 reinforcing member 562 isfixedly secured to channel member 112, by means of welding, riveting andthe like, at a location proximal of intermediate portion 112 c while adistal end of reinforcing member 562 is preferably slidably coupled todistal end 112 a via shoulders 580.

Reinforcing member 562 includes a first reinforcing plate 562 a having afirst pair of elongate recesses 590 a formed along each lateral sidethereof and extending in a longitudinal direction, wherein the firstpair of elongate recesses 590 a has a first length. Reinforcing member562 further includes a second reinforcing plate 562 b having a secondpair of elongate recesses 590 b formed in each lateral side thereof andextending in a longitudinal direction, wherein the second pair ofelongate recesses 590 b has a second length which is greater than thefirst length of first pair of elongate recesses 590 a. Reinforcingmember 562 further includes a third reinforcing plate 562 c having athird pair of elongate recesses 590 c formed in each lateral sidethereof and extending in a longitudinal direction, wherein the thirdpair of elongate recesses 590 c has a third length which is greater thanthe second length of the second pair of elongate recesses 590 b.

In operation, reinforcing member 562 functions in the same manner asreinforcing member 562. In particular, reinforcing member 562 increasesthe rigidity of channel member 112 only after channel member 112 hasundergone a predetermined amount of deflection in direction “Y”. Whentissue having a relatively larger thickness is clamped between distalends 104 a, 102 a of anvil half-section 104 and cartridge receivinghalf-section 102, deflection control system 560 causes distal end 104 aof anvil half-section 104 to undergo a four-stage deflection. In a firststage of deflection, distal end 112 a of channel member 112 undergoes aninitial rate of deflection, in direction “Y”, until the distal surfacesof the first pair of recesses 590 a of first reinforcement plate 562 acontacts shoulders 580 thus beginning a second stage of deflection.

In the second stage of deflection, distal end 112 a of channel member112 and first reinforcement plate 562 a undergo a second rate ofdeflection, in direction “Y”, until the distal surfaces of the secondpair of recesses 590 b of second reinforcement plate 562 b contactsshoulders 580, thus beginning a third stage of deflection. Since thedeflection force is now acting on distal end 112 a of channel member 112of anvil half-section 104 and on first reinforcement plate 562 a, thesecond rate of deflection is less than the first rate of deflection.

In the third stage of deflection, distal end 112 a of channel member 112and both first and second reinforcement plates 562 a and 562 b undergo athird rate of deflection, in direction “Y”, until the distal surfaces ofthe third pair of recesses 590 c of third reinforcement plate 562 ccontacts shoulders 580, thus beginning a fourth stage of deflection.Since the deflection force is now acting on distal end 112 a of channelmember 112 and both first and second reinforcement plates 562 a and 562b, the third rate of deflection is less than the second rate ofdeflection.

In the fourth stage of deflection, distal end 112 a of channel member112 and each of first, second and third reinforcement plates 562 a-562 cundergo a fourth rate of deflection, in direction “Y”. Since thedeflection force is now acting on distal end 112 a of channel member 112and on each of first, second and third reinforcement plates 562 a-562 c,the fourth rate of deflection is less than third rate of deflection.

At each stage of deflection, distal end 112 a of channel member 112 isfurther stiffened by the interaction of deflection control system 560with distal end 112 a of channel member 112. When the deflection, indirection “Y”, becomes greater than a predetermined amount, deflectioncontrol system 560 is engaged and distal end 112 a of channel member 112is stiffened. As described above, deflection control system 560 canprovide distal end 112 a of channel member 112 with multiple stages ofstiffening, however, it is within the scope of the present disclosurethat deflection control system 560 provides distal end 112 a of channelmember 112 with a single stage of stiffening.

As seen in FIGS. 8-12, reinforcing plates 462 a-462 c and reinforcingplates 562 a-562 c (for the sake of simplicity, hereinafter referred toas “reinforcing plates 462 a-462 c”) can each have a different thicknessfrom a distal end to a proximal end thereof. In this manner, the degreeof stiffening created by each reinforcing plate 462 a-462 c will bedifferent. In other words, a relatively thicker reinforcing plate willresult in a greater degree of stiffening while a relatively thinnerreinforcing plate will result in a lesser degree of stiffening. Whilereinforcing plate 462 a is shown as the thickest (i.e., providing thegreatest degree of stiffening) and reinforcing plate 462 c is shown asthe thinnest (i.e., providing the least degree of stiffening), it iscontemplated that the position of reinforcing plates 462 a and 462 c canbe reversed. It is further contemplated that any combination ofthicknesses and relative position of reinforcing plates 462 a-462 c canbe provided to achieve a desired degree and rate of stiffening of distalend 112 a of channel member 112.

Reinforcing plates 462 a-462 c are preferably each fabricated fromstainless steel, however, it is contemplated that reinforcing plates canbe fabricated from any material capable of increasing the rigidity ofdistal end 112 a of channel member 112, such as, for example, titanium,polycarbonate, fiberglass, resins and the like or any combinationthereof.

In each of the above-described deflection systems, it is desirable thatthe deflection system has a low profile or that the deflection system issituated to the lateral sides of channel member 112. In this manner,deflection systems will not result in the alteration of the depth ofknife track 122 and/or the operation of the knife blade (not shown)reciprocatingly disposed within knife track 122.

FIG. 17 is a graph illustrating the effects of use of any of thedeflection control systems disclosed herein. As seen in FIG. 17, fordeflection control systems having a reveal of about 0.004 to about 0.006inches a change in the rate of deflection, as evidenced by a change inthe slope of the corresponding plot, is experienced at approximately 15lbs. Also as seen in FIG. 17, for deflection control systems having areveal of about 0.010 inches a change in the rate of deflection, asevidenced by a change in the slope of the corresponding plot, isexperienced at approximately 34 lbs.

Turning now to FIGS. 18-23, a deflection control system, for controllingand/or reducing the rate of deflection of distal end 112 a of channelmember 112, in accordance with the preferred embodiment of the presentdisclosure, is shown generally as 640. Deflection control system 640includes a pair of parallel spaced apart juxtaposed reinforcing platesand/or ribs 344, each one secured to a respective side wall 114 ofchannel member 112.

Preferably, each reinforcing rib 344 is secured to side walls 114 ofchannel member 112 by welds 346. At least one weld 346, preferably apair of welds 346 a, 346 b can be used to secure each reinforcing rib344 to side wall 114. As seen in FIGS. 18-20, welds 346 a are providednear distal tip 112 d of channel member 112 and welds 346 b are providednear intermediate point 112 c of channel member 112. Preferably, welds346 b are provided proximal of intermediate point 112 c of channelmember 112 and of cam member 400 of anvil half-section 104. (see FIGS.2, 18 and 20)

Preferably, each reinforcing rib 344 is welded to a respective side wall114 such that an upper surface 344 d of reinforcing rib 344 contacts orsubstantially contacts an inner surface 116 a of base wall 116. As seenin FIGS. 21 and 22, a distal end 344 b of reinforcing rib 344 is weldedto side wall 114 such that upper surface 344 d of reinforcing rib 344 isin contact with inner surface 116 a of base wall 116. As seen in FIGS.21 and 23, a proximal end 344 c of reinforcing rib 344 is welded to sidewall 114 such that upper surface 344 d of reinforcing rib 344 is spaceda distance from inner surface 116 a of base wall 116.

Preferably, as seen in FIG. 7, each reinforcing rib 344 includes athrough hole H″ at or near proximal end 344 c thereof which aligns withand/or is in registration with a slot or hole H′ formed in each sidewall 114 of channel member 112 at or adjacent intermediate point 112 cof channel member 112. Preferably, a pin or cam member 400 (see FIGS. 2,18-21 and 23) extends through aligned holes H′ of channel member 112 andthrough holes H″ of each reinforcing rib 344, and in turn extendtransversely through side walls 114 of channel member 112 of anvilhalf-section 104. Such a cam member 400 and the manner in which itoperates is disclosed in International Appl. Ser. No. PCT/US03/08342filed on Mar. 13, 2003, the entire contents of which are incorporatedherein by reference.

Preferably, as best seen in FIG. 23, through-hole H″ of each reinforcingrib 344 has a diameter “D1” and the portion of cam 400 extending throughthrough-hole H″ of each reinforcing rib 344 has a diameter “D2” which isless than diameter “D1” of through-hole H″. In a preferred embodiment,diameter “D1” of through-hole H″ is about 0.203 inches and diameter “D2”of the portion of cam 400 extending through-hole H″ is about 0.200inches thereby defining a reveal of about 0.003 inches.

In operation, when tissue having a relatively smaller thickness isclamped between distal ends 104 a, 102 a of anvil half-section 104 andcartridge receiving half-section 102, distal end 104 a of anvilhalf-section 104 will tend to deflect an amount sufficient for tissuegap “G” to have a substantially uniform dimension from the proximal endto the distal end thereof.

When or as tissue having a relatively larger thickness is clampedbetween distal ends 104 a, 102 a of anvil half-section 104 and cartridgereceiving half-section 102, deflection control system 640 causes distalend 104 a of anvil half-section 104 to undergo a two-stage deflection.The rate of deflection is established when distal end 112 a of channelmember 112 and distal end 344 b of reinforcing ribs 344 are loaded witha force. When apparatus 100 is clamped onto relatively thin tissue, therate of deflection will be at a maximum to allow the tissue gap “G” tobe set relatively quickly. This maximum rate of deflection is attainedfrom the existent of the reveal between through-hole H″ of eachreinforcing rib 344 and the portion of cam 400 extending throughthrough-hole H″ of each reinforcing rib 344. When apparatus 100 isclamped onto relatively thicker tissue, the rate of deflection needs tobe reduced and/or at a minimum in order to maintain the proper tissuegap “G” for staple formation. This reduced rate of deflection isattained as a result of the size of the reveal between through-hole H″of each reinforcing rib 344 and the portion of cam 400 extending throughthrough-hole H″ of each reinforcing rib 344 being reduced to zero. Aswill be described in greater detail below, once the reveal is reduced tozero the rate of deflection is decreased to a desired and/or optimumrate.

In the first stage of deflection the deflection force acts on edgesurfaces 114 a of side walls 114 of channel member 112 resulting indistal end 104 a of anvil half-section 104 undergoing an initial rate ofdeflection in direction “Y”. Since each reinforcing rib 344 is welded toside walls 114, each reinforcing rib 344 travels with channel member112. Moreover, since distal end 104 a of anvil half-section 104 is urgedin the direction of arrow “Y”, as distal end 344 b of each reinforcingrib 344 is displaced in direction “Y”, proximal end 344 c of eachreinforcing rib 344 is displaced in a direction opposite to direction“Y” thereby engaging an upper portion of the rim 404 of through-hole H″formed in each reinforcing rib 344 towards an upper portion 402 of cam400 extending through-hole H″ and minimizing the reveal that existstherebetween. This first stage of deflection continues until the revealbetween upper portion of rim 404 of through-hole H″ and upper portion402 of cam 400 extending therethrough is reduced to zero. Once thereveal between upper portion of rim 404 of through-hole H″ and upperportion 402 of cam 400 is reduced to zero and upper portion of rim 404of through-hole H″ contacts with upper portion 402 of cam 400 extendingtherethrough, distal end 104 a of anvil half-section 104 undergoes asecond stage of deflection.

In the second stage of deflection, deflection control system 640 causesdistal end 104 a of anvil half-section 104 to undergo a rate ofdeflection which is less than the initial rate of deflection. Inoperation, since upper portion 404 of hole H″ is in contact with upperportion 402 of cam 400 extending therethrough, proximal end 344 c isprevented from moving further in the direction opposite to arrow “Y”.Accordingly, since distal end 344 b of reinforcing ribs 344 are urged inthe direction of arrow “Y”, the prevention of movement of proximal end344 c of reinforcing ribs 344 in the direction opposite to direction “Y”prevents movement of distal end 344 b of reinforcing ribs 344 indirection “Y”, thereby reinforcing distal end 104 a of anvilhalf-section 104 and reducing the rate of deflection thereof.

Deflection control system 640 in effect prevents the distal end oftissue gap “G” from having a reverse tapered configuration (i.e., thedistal end having a larger height than the proximal end).

It is contemplated that surgical stapling apparatus 100 can be providedwith directionally biased formable staples and/or be provided with anvilpockets for forming the staples in a predetermined manner. Such asurgical stapling apparatus is disclosed in U.S. application Ser. No.09/693,379 filed on Oct. 20, 2000, entitled “Directionally BiasedStaples and Cartridge Having Directionally Biased Staples”, the entirecontents of which are incorporated herein by reference.

In each of the embodiments disclosed herein, the deflection controlsystems reduce the degree and/or amount of deflection of distal end 112a of channel member 112, and in turn the degree and/or amount ofdeflection of distal end 104 a of anvil half-section 104, of surgicalfastener applying apparatus 100, as compared to a surgical fastenerapplying apparatus not including a deflection control system accordingto any of the embodiments disclosed herein.

It will be understood that the particular embodiments described aboveare only illustrative of the principles of the disclosure, and thatvarious modifications can be made by those skilled in the art withoutdeparting from the scope and spirit of the disclosure.

What is claimed is:
 1. A surgical fastener applying apparatus,comprising: an anvil half-section including a distal end and a proximalend defining a longitudinal axis, the anvil half-section including achannel member having pair of juxtaposed side walls interconnected by abase wall, the anvil half-section being pivotable about a pivot axisextending transversely to the longitudinal axis; and a deflectioncontrol system operatively associated with the anvil half-section forreinforcing the distal end of the anvil half-section when a force isapplied to the distal end of the anvil half-section in a directiontransverse to the longitudinal axis, the deflection control systemincluding: a pair of reinforcing ribs each including a distal end and aproximal end, wherein the distal end of each reinforcing rib is fixedlysecured, at a respective distal fixation point, to a respective sidewall of the pair of side walls of the channel member and wherein each ofthe reinforcing ribs is fixedly secured, at a respective proximalfixation point, a respective side wall of the pair of side wall of thechannel member at a location proximal of the distal fixation points,wherein the proximal end of each reinforcing rib extends beyond thepivot axis.
 2. The surgical fastener applying apparatus according toclaim 1, wherein each of the first and second fixation points includeswelds between the ribs and the respective side walls of the anvilhalf-section.
 3. The surgical fastener applying apparatus according toclaim 2, wherein each side wall of the anvil half-section defines athrough hole having a diameter, and wherein the proximal end of eachreinforcing rib defines a hole in registration with the through holedefined in the side walls of the channel member, the holes beingpositioned proximal of the pivot axis; the surgical fastener applyingapparatus further comprising: a cartridge receiving half-sectionincluding a distal end, wherein the cartridge receiving half-section ispivotably couplable with the anvil half-section such that the distal endof the anvil half-section is in juxtaposed relation to the distal end ofthe cartridge receiving half-section, wherein the distal end of theanvil half-section is pivotable relative to the distal end of thecartridge receiving half-section about the pivot axis; and a camextending through the holes formed in each side wall of the channelmember and each reinforcing rib, the cam having a diameter smaller thanthe diameter of the through hole formed in each reinforcing rib tothereby define a reveal between each reinforcing rib and the cam.
 4. Thesurgical fastener applying apparatus according to claim 3, wherein thesecond stage of deflection takes effect when the reveal between an upperportion of the hole formed in each reinforcing rib and an upper portionof the cam is zero.
 5. A surgical fastener applying apparatus,comprising: an anvil half-section defining a tissue contacting surface,the anvil half-section including a distal end, a proximal end thatdefines a longitudinal axis, and a pair of side walls; and a deflectioncontrol system operatively associated with the anvil half-section,wherein the deflection control system includes a pair of reinforcingribs, each rib of the pair of reinforcing ribs being disposed along aninner surface of a respective side wall of the pair of side walls of theanvil half-section, wherein each rib of the pair of reinforcing ribs isfixedly secured to a respective side wall of the anvil half-section at adistal fixation point and at a proximal fixation point, wherein thedeflection control system reinforces the distal end of the anvilhalf-section when a force is applied to the distal end of the anvilhalf-section in a direction transverse to the longitudinal axis, andnormal to a plane defined by the tissue contacting surface of the anvilhalf-section, whereby the distal end of the anvil half-section and thedistal end of the reinforcing ribs deflect concomitantly.
 6. Thesurgical fastener applying apparatus according to claim 5, wherein theproximal end of each reinforcing rib extend proximally beyond a pivotaxis of the anvil half-section, wherein the pivot axis extendstransverse to a longitudinal axis of the anvil half-section.
 7. Thesurgical fastener applying apparatus according to claim 6, wherein theproximal fixation points are located proximal of the pivot axis.
 8. Thesurgical fastener applying apparatus according to claim 7, wherein eachof the first and second fixation points includes welds between the ribsand the respective side walls of the anvil half-section.
 9. The surgicalfastener applying apparatus according to claim 8, further comprising: acartridge receiving half-section including a distal end, wherein thecartridge receiving half-section is operatively couplable with the anvilhalf-section such that the distal end of the anvil half-section is injuxtaposed relation to the distal end of the cartridge receivinghalf-section, and wherein a tissue gap is defined between the distal endof the anvil half-section and the distal end of the cartridge receivinghalf-section when the anvil half-section and the cartridge receivinghalf-section are coupled together.
 10. The surgical fastener applyingapparatus according to claim 9, wherein each side wall of the anvilhalf-section defines a through hole having a diameter, and wherein theproximal end of each reinforcing rib defines a hole in registration withthe through hole defined in the side walls of the channel member, theholes being positioned proximal of the pivot axis.
 11. The surgicalfastener applying apparatus according to claim 10, wherein the cartridgereceiving half-section is pivotably couplable with the anvilhalf-section such that the distal end of the anvil half-section is injuxtaposed relation to the distal end of the cartridge receivinghalf-section, wherein the distal end of the anvil half-section ispivotable relative to the distal end of the cartridge receivinghalf-section about the pivot axis.
 12. The surgical fastener applyingapparatus according to claim 11, further comprising: a cam extendingthrough the holes formed in each side wall of the channel member andeach reinforcing rib, the cam having a diameter smaller than thediameter of the through hole formed in each reinforcing rib to therebydefine a reveal between each reinforcing rib and the cam.